Pneumococcal IgM response following vaccination. (A) Pneumococcal IgM titers are presented at 4 weeks following vaccination in healthy controls and CML patients on TKI. A positive IgM pneumococcal response was defined as a fourfold rise in serum IgM titers or an IgM titer >200 U/mL 4 weeks postimmunization irrespective of the preimmunization titer. (B) The pneumococcal IgM response is presented before and 4 weeks after vaccination in responders (black lines) and nonresponders (dashed lines) for healthy controls and CML patients on TKI. (C) The postimmunization pneumococcal IgM titers are presented for CML patients on imatinib, nilotinib, and dasatinib. Bars represent medians with interquartile range.